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Status of Sport Fishes in Graham Lake, Alberta, 2004

Author(s)

Greg Fortier, Tyler Johns, and John Tchir

Summary

Increased access in the Red Earth area in the Northwest region of Alberta, resulting from the development of new roads, has raised concerns about impacts of potential increases in angling pressure on sport fish populations of lakes in the region, including Graham Lake. The present study was conducted on Graham Lake to generate quantitative data on abundance, population structure, and growth of four major sport fish species, walleye (Sander vitreus), northern pike (Esox lucius), lake whitefish (Coregonus clupeaformis), and yellow perch (Perca flavescens), that can be used to assess impacts of the increased fishing pressure.

A total of 635 sport fish were captured during the survey of which lake whitefish was the most abundant, accounting for 42.4% of the catch; walleye, northern pike, and yellow perch constituted 13.9, 4.3, and 12.8% of the total catch, respectively.

Catch-per-unit-effort (CPUE) for walleye ranged from 1.26 to 8.13 fish/100m2/24h with a mean (±95% CI) of 5.14 ± 2.60 fish/100m2/24h (n = 10). Of the 88 walleye sampled, 63.6% were females and 36.4% were males, resulting in a female to male sex ratio of 1.75:1. Length of females ranged from 109 to 645 mm FL with a mean (±SD) of 470.5 ± 155.70 mm (n = 56) while that of males ranged from 186 to 581 mm with a mean of 471.3 ± 99.83 mm (n = 32). Males ranged in age from 3 to 16 y with a mean (±SD) of 11.7 ± 3.41 y (n = 29) while age of females ranged from 1 to 17 y with a mean of 9.7 ± 5.26 y (n = 54). Overall mean age of the catch was 10.4 ± 4.77 y (n = 83).

CPUE for northern pike ranged from 0.38 to 3.43 fish/100m2/24h with a mean of 1.46 ± 1.00 fish/100m2/24h (n = 10). Of the 27 northern pike sampled, 74.1% were females and 25.9% were males, resulting in a female to male sex ratio of 2.86:1. Length of females ranged from 570 to 888 mm FL with a mean of 719.3 ± 75.17 mm (n = 20) while that of males ranged from 418 to 654 mm with a mean of 572.1 ± 78.08 mm (n = 7). Males ranged in age from 3 to 13 y with a mean of 7.8 ± 3.37 y (n = 6) while age of females ranged from 4 to 16 y with a mean of 9.7 ± 2.98 y (n = 19). Overall mean age of the catch was 9.2 ± 3.11 y (n = 25).

CPUE for lake whitefish ranged from 12.38 to 17.46 fish/100m2/24h with a mean of 14.76 ± 4.91 fish/100m2/24h (n = 10). Of the 265 lake whitefish sampled, 64.5% were females and 35.5% were males, resulting in a female to male sex ratio of 1.82:1. Length of females ranged from 260 to 581 mm FL with a mean of 450.3 ± 50.16 mm (n = 171) while that of males ranged from 252 to 526 mm with a mean of 439.6 ± 43.89 mm (n = 94). Males ranged in age from 2 to 12 y with a mean of 8.1 ± 2.55 y (n = 59) while age of females ranged from 2 to 16 y with a mean of 9.16 ± 2.93 y (n = 68). Overall mean age of the catch was 8.7 ± 2.8 y (n = 127).

CPUE for yellow perch ranged from 1.62 to 5.81 fish/100m2/24h with a mean of 4.55 ± 2.45 fish/100m2/24h (n = 10). Of the 79 yellow perch sampled, 91.1% were females and 8.9% were males, resulting in a female to male sex ratio of 10.29:1. Length of females ranged from 93 to 238 mm FL with a mean of 158.7 ± 18.67 mm (n = 72) while that of males ranged from 88 to 181 mm with a mean of 140.9 ± 29.00 mm (n = 7). Males ranged in age from 2 to 4 y with a mean of 3.2 ± 0.75 y (n = 6) while age of females ranged from 2 to 7 y with a mean of 3.2 ± 0.65 y (n = 71). Overall mean age of the catch was 3.2 ± 0.64 y (n = 79).

The results of the present study provide important baseline information that can be used by resource managers to quantify the effects of anticipated increases in angling pressure on sport fish population in Graham Lake.